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Topic:Skin
The skin of horses is a complex organ that serves multiple functions, including protection, thermoregulation, and sensory perception. It consists of several layers, primarily the epidermis and dermis, each contributing to the overall health and functionality of the skin. The epidermis provides a barrier against environmental factors, while the dermis supports the skin structure and houses blood vessels, nerves, and hair follicles. Equine skin is also involved in the production of sweat and sebum, which aid in temperature regulation and skin lubrication, respectively. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and health conditions of equine skin, as well as advancements in dermatological treatments and care practices.
Readability of branding symbols in horses and histomorphological alterations at the branding site. Identification of horses has traditionally been facilitated by hot iron branding, but the extent by which branding symbols and numbers can be identified has not been investigated. The local pathological changes induced by branding are also unknown. This study analysed the readability of branding symbols and histomorphological alterations at the branding sites. A total of 248 horses in an equestrian championship were available for identification of symbols and numbers. A further 28 horses, euthanased for other reasons, provided histological examination of the branding site. All except one horse...
Temperature regulation in horses during exercise and recovery in a cool environment. Clipping the winter coat in horses is done to improve heat dissipation during exercise and make grooming easier. It is often combined with blanketing to keep the horse warm. The aims of the present study were to investigate how clipping and the use of blankets affect thermoregulation during exercise and recovery in horses. Methods: One Gotland pony, one New Forest pony, and one warm-blooded horse exercised one after the other on a 6450 m long track. The horses walked, trotted and cantered according to a predetermined scheme, which took about 50 minutes including three stops. The scheme was rep...
RACK1, a clue to the diagnosis of cutaneous melanomas in horses. Melanocytic proliferations are common in horses but the diagnosis of malignancy is not always straightforward. To improve diagnosis and prognosis, markers of malignancy are needed. Receptor for activated C kinase 1 (RACK1) protein may be such a marker. RACK1 was originally found to characterize malignant melanocytic lesions in the Melanoblastoma-bearing Libechov minipig (MeLiM) and, later, in human patients. Our purpose was to investigate the value of RACK1 in the classification of cutaneous melanocytic proliferations in horses. Results: Using immunofluorescence, we report here that both MITF ...
Skin temperature during cutaneous wound healing in an equine model of cutaneous fibroproliferative disorder: kinetics and anatomic-site differences. To map skin temperature kinetics, and by extension skin blood flow throughout normal or abnormal repair of full-thickness cutaneous wounds created on the horse body and limb, using infrared thermography. Methods: Experimental. Methods: Standardbreds (n = 6), aged 3-4 years. Methods: Three cutaneous wounds were created on the dorsolateral surface of each metacarpus and on the lateral thoracic wall. Thoracic skin wounds and those on 1 randomly chosen forelimb healed by second intention without a bandage, whereas contralateral limb wounds were bandaged to induce formation of exuberant granulation...
Effects of mesenchymal stem cells isolated from amniotic fluid and platelet-rich plasma gel on severe decubitus ulcers in a septic neonatal foal. This paper documents the treatment of severe decubitus ulcers with amniotic fluid mesenchymal stem cells and platelets rich plasma (PRP) gel in a septic neonatal foal. The colt needed 25 days of hospitalization: during this period ulcers were treated for 15 days with mesenchymal stem cells (MSCs) plus PRP, PRP gel alone, or aloe gel. Healing was faster using MSCs+PRP, and at 7 months an ulcer treated with aloe gel was still not completely healed.
Mycobacterium DNA detection in liver and skin of a horse with generalized sarcoidosis. Sarcoidosis is a rare equine skin disease characterized primarily by an exfoliative and granulomatous dermatitis but also presenting granulomatous inflammation of multiple systems. The current report presents the clinical and histopathological findings of sarcoidosis in a 16-year-old American Quarter Horse gelding with nested polymerase chain reaction Mycobacterium spp. DNA detection within hepatic and skin samples. Mycobacterium spp. may play a role in the pathogenesis of equine sarcoidosis as has been proposed for human sarcoidosis.
The approach to the equine dermatology case in practice. A logical and thorough clinical investigation should provide the best basis for the diagnosis of skin diseases. Where no diagnosis can be reached despite a full range of investigations, the clinician can justifiably attempt symptomatic treatment, but it is always better to focus treatment on a specific condition based on properly accumulated and tested clinical evidence. Unfortunately, in equine dermatology there are few text descriptions of the majority of the conditions encountered in practice. While a few diseases are well recognized, there is still little consensus on the best treatments f...
Wound care in horses. Care of equine wounds in the field can be a challenging endeavor. Many times, wound care is complicated by chronicity or by prior inappropriate care in addition to the great degree of tissue trauma that occurred when the horse was wounded. Recognizing involvement of synovial structures, loss of skin, and damage to bone are critical in the initial examination of wounds and will guide future care. Education of clients is also important in that preparing them for possible outcomes during healing may help improve compliance and proper treatment of wound. Owners and trainers often perform much of t...
Methicillin-resistant Staphylococcus aureus (MRSA) on the skin of long-term hospitalised horses. Given the significance of methicillin-resistant Staphylococcus aureus (MRSA) infections for both horses and staff in equine veterinary hospitals, protocols are required to minimise the risk of nosocomial transmission, including the screening of the skin and nasal chambers of equine patients for evidence of infection. The objective of this study was to clarify the potential existence and extent of MRSA on the skin of horses requiring long-term hospitalisation (≥ 6 months). Thirty such horses were sampled at eight different locations on their skin and from their nasal chambers. MRSA was isolat...
Localization of Bovine papillomavirus in equine sarcoids and inflammatory skin conditions of horses using laser microdissection and two forms of DNA amplification. Equine sarcoids are the most common tumor of horses. Bovine papillomavirus (BPV) has been suggested as the cause of sarcoids. Studies have shown that BPV is present in swabs or biopsies from nonsarcoid-bearing equine skin. Skin biopsies from a variety of different conditions and normal skin from horses with no reported history of sarcoids were examined by polymerase chain reaction (PCR) for the presence of BPV, which was found in all different types of skin conditions as well as normal skin. Forty-one out of 86 skin biopsies from horses without sarcoids were found to contain BPV DNA. Laser mic...
A case of Borrelia-associated cutaneous pseudolymphoma in a horse. This case report describes a 10-year-old horse that developed multiple dermal papules over the right masseter area following removal of a tick from the same site 3 months earlier. Histological examination of a biopsy from a papule was suggestive of either a T-cell-rich B-cell lymphoma or cutaneous lymphoid hyperplasia, a form of pseudolymphoma sometimes associated with a tick bite. Positive serological testing and PCR of the biopsy sample for Borrelia in conjunction with immunohistochemical testing of the skin biopsy, the clinical history and response to treatment with doxycycline strongly sup...
Optimization of a Staphylococcus aureus adhesion assay for equine corneocytes. Meticillin-resistant Staphylococcus aureus (MRSA) causes serious skin and soft-tissue infections of humans and animals. Multiple strains of MRSA have been characterized, and one in particular, designated as strain USA 500, causes infections predominantly of horses and the people who work with them. The purpose of this study was to optimize an assay which could subsequently be used to compare the relative avidity of different S. aureus strains for equine corneocytes. Corneocytes were collected from the perineal skin of 10 healthy horses onto adhesive discs. The discs were then incubated at 37°...
Equid herpesvirus 5-associated dermatitis in a horse–Resembling herpes-associated erythema multiforme. An equid herpesvirus 5 (EHV-5) infection was detected in lesioned skin from a nine-year-old Holsteiner stallion in the south of Germany. Macroscopically, the animal displayed a non-pruritic, multifocal, pustular dermatitis around both eyes, nostrils and the muzzle, which had been ongoing for one year. Histopathologically, skin lesions were characterized by orthokeratotic to parakeratotic hyperkeratosis, pustular dermatitis, epidermal hyperplasia, apoptotic keratinocytes, a lympho-plasmahistiocytic interface dermatitis with hydropic degeneration of keratinocytes, and perivascular to diffuse, ly...
Identification of a melanocyte-specific, microphthalmia-associated transcription factor-dependent regulatory element in the intronic duplication causing hair greying and melanoma in horses. Greying with age in horses is an autosomal dominant trait, characterized by hair greying, high incidence of melanoma and vitiligo-like depigmentation. Previous studies have revealed that the causative mutation for this phenotype is a 4.6-kb intronic duplication in STX17 (Syntaxin 17). By using reporter constructs in transgenic zebrafish, we show that a construct containing two copies of the duplicated sequence acts as a strong enhancer in neural crest cells and has subsequent melanophore-specific activity during zebrafish embryonic development whereas a single copy of the duplicated sequence a...
A preliminary study on the effect of manuka honey on second-intention healing of contaminated wounds on the distal aspect of the forelimbs of horses. To determine the effect of manuka honey on second-intention healing of contaminated, full-thickness skin wounds in horses. Methods: Experimental. Methods: Adult Standardbred horses (n = 8). Methods: One wound was created on the dorsomedial aspect of the third metacarpus in both forelimbs, contaminated with feces, and bandaged for 24 hours. Bandages were removed and wounds rinsed with isotonic saline solution. Wounds on 1 limb had manuka honey applied daily (n = 8) whereas wounds on the contralateral limb received no treatment (n = 8). Bandages were replaced and changed daily for 12 days, after...
The percutaneous permeation of a combination of 0.1% octenidine dihydrochloride and 2% 2-phenoxyethanol (octenisept®) through skin of different species in vitro. A water based combination of 0.1% octenidine dihydrochloride and 2% 2 - phenoxyethanol is registered in many European countries as an antiseptic solution (octenisept®) for topical treatment with high antimicrobial activity for human use, but octenidine based products have not been registered for veterinary use yet. The aim of the present study was to investigate whether octenidine dihydrochloride or 2 -phenoxyethanol, the two main components of this disinfectant, permeate through animal skin in vitro. Therefore, permeation studies were conducted using Franz-type diffusion cells. 2 ml of the t...
The clinical presentation and surgical treatment of verrucous dermatitis lesions in a draught horse. Verrucous pastern dermatitis is a progressive inflammatory skin disease commonly involving the palmar or plantar aspects of the pasterns of horses. There are no reports of successful surgical treatment for multifocal circumscribed verrucous masses in the chronic stages of verrucous pastern dermatitis. A combination of sharp dissection and electrocautery was used to resect numerous multifocal circumscribed verrucous masses from the distal hindlimb of an 11-year-old gelding draught horse. There was no evidence of significant regrowth or complications at a 24 month postoperative examination.
Equine atopic skin disease and response to allergen-specific immunotherapy: a retrospective study at the University of California-Davis (1991-2008). This retrospective study reports on the clinical presentation of equine atopic skin disease and evaluates response to treatment with allergen-specific immunotherapy (ASIT) based on intradermal testing and/or serum testing. Computerized medical records from January 1991 to December 2008 yielded 54 horses included in the study. Presenting clinical signs (CS) included urticaria (n=28), pruritus (n=8) or both (n=18). Forty-one of 54 horses received ASIT, and response to ASIT (n=32) was evaluated via telephone survey. Eighty-four per cent (n=27) of owners reported that ASIT reduced their horse's CS...
Constitutive expression of hypoxia-inducible factor-1 α in keratinocytes during the repair of skin wounds in horses. As a transient hypoxic state exists within skin wounds in horses and may be important for the healing process, this study sought to identify a molecular hypoxia response occurring in horse limb and body wounds healing by second intention. Hypoxia-inducible factor 1α (HIF1α) protein expression was studied throughout repair by Western blotting and immunofluorescence. Paradoxically, HIF1α was strongly expressed in intact skin and its expression decreased dramatically following wounding (p<0.01), despite the expected hypoxic state within the wounded tissue. HIF1α levels reincreased in parallel...
Cutaneous asthenia in a Warmblood foal. A 6-week-old Warmblood colt foal was presented for investigation of multiple haematoma formation in various locations, poor wound healing and abnormal scar formation. Based on the history and clinical presentation of hyperextensible skin with prolonged skin tenting, the foal was diagnosed with cutaneous asthenia and euthanased because of the poor prognosis. Histopathological and electron microscopic findings were inconclusive. This is the first case report of cutaneous asthenia in a Warmblood horse in Australia. Cutaneous asthenia is reviewed with particular reference to hereditary equine regi...
Successful treatment of equine sarcoids by topical aciclovir application. Based on the anecdotally reported eradication of a sarcoid using aciclovir cream, the curative potential of this ointment was investigated in 22 sarcoid-affected horses referred to the Equine Clinic Tillysburg, Austria, between 2006 and 2009. Sarcoid disease was diagnosed by clinical examination and bovine papillomavirus types 1 and 2 from intact skin and tumour tissue. As nine horses had more than one lesion, a total of 47 sarcoids were treated by daily topical application of aciclovir 5 per cent cream for a period of two to six months; in four horses, surgical tumour ablation was performed b...
The healing effects of a topical phytogenic ointment on insect bite hypersensitivity lesions in horses. Insect bite hypersensitivity (IBH) is the most common cause of pruritus in horses and is a serious welfare issue for affected animals. In this study, the effect of a topical phytogenic ointment on the healing of cutaneous lesions was investigated in a double-blind trial involving 26 horses with I B H. The number of lesions and their total surface area were recorded on days 0, 7, and 21 in horses treated for 3 weeks with either verum or placebo ointment. After unblinding of treatment assignment, the horses that had been treated with the placebo ointment received the verum preparation for an add...
Severe bilaterally symmetrical alopecia in a horse. A 9-year-old Tennessee Walking Horse gelding was presented for diagnosis of the cause of extensive alopecia. Complete hair loss was noted over the head, neck, shoulder, thigh, and proximal limbs, but the trunk, distal limbs, pelvic area, mane, and tail were unaffected. The alopecic areas were visually noninflammatory with no exudate or crust except on the shoulder and along the back, where multifocal patchy areas of alopecia with scales and crust were evident. The horse was slightly pruritic. Microscopically, the hair bulbs, inner and outer root sheaths of inferior segments, and perifollicular...
Glomus tumours in the skin and subcutis of three horses. Three horses presented with variably painful, nonulcerated masses of the head or neck that were diagnosed as glomus tumours. Grossly, they were fleshy, pink to tan masses ranging from 0.4 to 9 cm in diameter, involving either the deep dermis and subcutis or the subcutis and underlying skeletal muscle. Microscopically, neoplastic epithelioid cells were arranged in sheets, cords and packets within lobules. The neoplastic cells frequently abutted and formed nodular bulges into large endothelium-lined vascular spaces, especially around the tumour periphery. Large nerve branches were associated wit...
BPV-1 infection is not confined to the dermis but also involves the epidermis of equine sarcoids. In equids, bovine papillomaviruses of type 1 (BPV-1) and less frequently type 2 induce common, locally aggressive skin tumours termed sarcoids. Whereas BPV infection in cattle usually involves the epidermis and is productive in this skin layer, infection in equids is currently thought to be abortive, with virus solely residing as multiple episomes in dermal fibroblasts. Based on recent observations that do not agree with this assumption, we hypothesised that BPV also infects equid epidermis and is active in this skin layer. To test this hypothesis, we conducted a proof-of-principle study on ei...
Cutaneous fungal granulomas due to Alternaria spp. infection in a horse in New Zealand. Equine cutaneous fungal granulomas have been previously referred to in New Zealand (Fairley 1998), and are described in the veterinary literature from around the world, including North America and Australia (Pascoe and Summers 1981; Genovese et al. 2001; Valentine et al. 2006), but no peer-reviewed reports appear published in the literature in New Zealand. Described here is a case of multiple cutaneous fungal granulomas caused by Alternaria spp. in a horse in New Zealand.
Skin-infiltrating T cells and cytokine expression in Icelandic horses affected with insect bite hypersensitivity: a possible role for regulatory T cells. Equine insect bite hypersensitivity (IBH) is a seasonally recurrent, pruritic skin disorder caused by an IgE-mediated reaction to salivary proteins of biting flies, predominantly of the genus Culicoides. The aim of this study was to define T cell subsets and cytokine profile in the skin of IBH-affected Icelandic horses with particular focus on the balance between T helper (Th) 1, Th2 and T regulatory (Treg) cells. Distribution and number of CD4+, CD8+ and Forkhead box P3 (FoxP3)+ T cells were characterized by immunohistochemical staining in lesional and non-lesional skin of moderately and seve...
A survey of aged horses in Queensland, Australia. Part 2: Clinical signs and owners’ perceptions of health and welfare. To describe the prevalence and risk factors for clinical signs of disease and owner-reported health or welfare issues of aged horses in Queensland, Australia. Methods: Owners of horses were contacted via an equestrian organisation in Queensland and asked to complete a questionnaire about their horses aged 15 years and older, to gain information about clinical signs observed in the horse and disease history. Owners were asked to identify health or welfare issues they felt were important in aged horses. Results: Owners were able to identify many clinical signs of disease, with 83% of horses havi...
